Arnot, a medical correspondent for CBS This Morning and 48 Hours , has compiled a consumer's guide to getting the most from the present health care system. He bases his recommendations on scores of interviews with health care professionals and data collected from ``research firms, think tanks, medical schools and articles published in medical journals.''x This is the ``blue book'' of medicine--and Arnot wouldn't mind the analogy to hardheaded comparison shopping in a used-car lot. His work is an invaluable tool for those who wish to improve the health care they or their loved ones receive. The two main sections are guides: the first covers surgical procedures, and the second deala with managing chronic diseases. In both, Arnot furnishes information about diagnoses, potential treatment risks and alternatives, and how to choose a doctor. He also lists nationwide ``centers of excellence'' for treatments and various support groups. In a country where, by some reports, 25% of all of the surgeries performed are unnecessary, this book will help the reader choose better odds. (Sept.)